Origin and Habitat: Bolson de Mapimi (a.k.a. Comarca Lagunera), Durango, center-north of the Mexican Plateau.
Altitude: 1000-1200 m above sea level.
Habitat: The Bolson de Mapimi is a semi-desert plateau generally low and flat, closed at the bottom and surrounded on all sides by mountain slopes and covered for part of the year by lagoons, which during the rainy season overflow through the rivers Nazas and Aguanaval. The bottom of such lagoons are typically occupied by unvegetated shallow salt lakes or salt pans. The lowest area of a bolson is called the playa, and the lakes that form there are known as playa lakes. Although some playa lakes are nearly permanent, most are ephemeral. Vegetation is usually restricted to low gravelly hills in typical chihuahuan desert formations. This area is particularly rich of succulent endemisms such as: Coryphantha validaSN|10197]]SN|10249]], Coryphantha poselgeriana, Coryphantha macromerisSN|10268]]SN|10268]], Coryphantha kraciki, Coryphantha difficilisSN|10249]]SN|10197]], Corynopuntia grahami, Epithelantha micromerisSN|6936]]SN|6936]], Echinomastus durangensisSN|14915]]SN|14907]], Echinomastus mapimiensisSN|14907]]SN|14915]], Echinocereus stramineusSN|7817]]SN|7817]], Glandulicactus uncinatusSN|3474]]SN|3474]], Ibervillea sonorae, Mammillaria lasiacanthaSN|9355]]SN|9075]], Mammillaria grusoni, Mammillaria gasseriana, Mammillaria pottsiiSN|9075]]SN|9355]], Peniocereus greggiiSN|8088]]SN|8088]], Thelocactus bicolorSN|3420]]SN|3420]], Ariocarpus fissuratusSN|2114]]SN|2114]] v. lloydyi etc.

• Echinomastus mapimiensis Backeb.
• Echinomastus durangensis var. mapimiensis (Backeb.)

• Echinomastus unguispinus (Engelm.) Britton & Rose
• Echinocactus unguispinus Engelm. in Wisliz.
• Neolloydia unguispina (Engelm.) L.D.Benson
• Sclerocactus unguispinus (Engelm.) N.P.Taylor
• Thelocactus unguispinus (Engelm.) W.T.Marshall
• Echinomastus mapimiensis Backeb.
• Echinomastus durangensis var. mapimiensis (Backeb.)
• Echinomastus unguispinus subs. durangensis (C.Runge) U.Guzmán
• Echinocactus durangensis C.Runge
• Echinomastus durangensis (C.Runge) Britton & Rose
• Echinomastus unguispinus var. durangensis (C.Runge) Bravo
• Neolloydia durangensis (C.Runge) L.D.Benson
• Pediocactus unguispinus var. durangensis (C.Runge) Halda
• Sclerocactus unguispinus var. durangensis (C.Runge) N.P.Taylor
• Thelocactus durangensis (C.Runge) W.T.Marshall
• Echinomastus unguispinus subs. laui (G.Frank & Zecher) Glass
• Echinomastus laui G.Frank & Zecher
• Echinomastus unguispinus var. laui (G.Frank & Zecher) Glass & R.A.Foster

Description: Plants solitary with spines almost hiding the body.
Stem: globose to short cylindrical 8-11 cm tall, 7-9 cm in diameter, gray-green or bluish green.
Ribs: 18-20 low, tuberculate
Radial spines: White to yellowish brown to blue-gray with black apex, becoming gray with age,15-30 mm long irregularly spreading, some interlacing.
Central spines: Stronger, 3-6, white to brownish but occasianally black, the upper side is always darker than the bottom side, straight to curved,15-20 mm long, directed upwards, lower one pointing outward and downward.
Flowers: Funnelform, dirty brownish red or yellowish- brown, up to 2.5 cm in diameter.

Bibliography: Major references and further lectures
1) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
2) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
3) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
4) Gómez-Hinostrosa, C. & Hernández, H.M. 2013. Sclerocactus unguispinus. In: IUCN 2013. "IUCN Red List of Threatened Species." Version 2013.2. <www.iucnredlist.org>. Downloaded on 06 April 2014.

Cultivation and Propagation: This is one of the most beautiful cacti but rarely seen in cultivation, it needs perfect drainage to flourish. It is quite difficult to grow on its own roots. Very easily rot! It’s thought that’s better to watch this species in photo or in the natural habitat rather than to try to cultivate it. For this reasons the plant is often grafted on a frost hardy stock.
Soil: Give an open soil that drains fast, and avoid mixtures containing peat or any other form of sphagnum moss.
Exposure: This plant need full sun and above all a very good ventilation, especially in winter.
Water requirements: Keep totally dry during winter, and in summertime make sure that the soil dries enough between waterings. It can tolerate temperature below zero (-5° C or less).
Remarks: Mature individuals - if the growing conditions are not optimal, easily rot and die.
Propagation: Seeds are relatively difficult to germinate (only a limited percentage of seeds germinate). Moreover it is easy for the seed to get lost behind the spines, which are stiff enough that when you try to retrieve them you just might loose them altogether. Grafting is often used to speed growth rate and to create a back-up for plants in collection.